It’s a very fitting place for a magic shop. Hidden away in the maze of pedestrian tunnels that lead from Covent Garden to Charing Cross station, Davenports certainly takes some finding. But that’s to the good — a complete absence of passing trade means they no longer have to stock stink bombs and novelties, as they did in their old location opposite the British Museum. These days Davenports concentrate solely on the proper stuff. The shelves boast Svengali decks and thumb tips, gimmicks like the Raven (it’s a beauty), and instructional DVDs and books by everyone from David Devant to Roy Walton.

If those names are familiar to you, you’re probably a pro. The business has been supplying magicians with the tools of their trade since Lewis Davenport first set up shop in 1898. But if the names mean nothing, don’t worry — you’re still very welcome to come in and begin your journey of discovery. You can turn up, have a trick or two demonstrated to you by the staff, then purchase the props (and secrets) to take home. Remember the mantra: ‘Practise and practise until you are sore — then you are ready to practise once more.’

Or you could attend one of the regular classes run for both adults and children. The latter, says Bill Davenport (Lewis’s great-grandson), are ‘always the most difficult audience. You can show a trick to an engineer with several PhDs and they’ll try to work it out logically, and almost certainly fail. But kids have that wonderful way of thinking that breaks all the rules. They’re the ones who’ll catch you out.’

Chatting to Bill, I nervously make a confession: I love telling people the secrets behind tricks. I know a dozen or so, using everyday objects and requiring no great sleight of hand. There’s an absolutely baffling mindreading effect with a pair of books — you can even do it at someone’s house with their own books, so they know there’s no cheating (or at least none they can spot). The joy comes in sharing the secret, rather as you want to share any great joke you hear. I’ve always disliked people who insist on showing you a trick but then won’t reveal how they did it. That’s when magic puts distance between people, rather than bringing them together.

But of course I’d never reveal any secrets in print. And I’ve no problem with people wanting to be mystified. Even Bill has that desire sometimes. ‘I went to see David Copperfield, and he did his flying illusion. For a minute or two I sat there trying to spot the wires and couldn’t. Then I realised I’d enjoy the experience much more if I simply relaxed and took it on its own terms. That’s what magic should be about.’

I once watched a ‘busking’ magician in a London pub entertain the people at the table next to mine. One woman loved a particular card trick so much she gave him a fiver. After he’d left, and as they were still chatting about the trick, I asked: ‘If I tell you how he did it will you give me a fiver too?’ She went mental. ‘Don’t you dare ruin it for me!’

It’s people like that who are going to keep Davenports in business for a very long time to come.